FCRONTAB(5)                                                        FCRONTAB(5)



NAME
       fcrontab - tables for driving fcron

DESCRIPTION
       A fcrontab is a file containing all tables used by the fcron(8) daemon.
       In other words, it is the means for a user to tell the daemon "execute
       this command at this moment". Each user has their own fcrontab, whose
       commands are executed as their owner (only root can run a job as
       another using the option runas (see below)).

       Blank lines, line beginning by a hash sign (#) (which are considered
       comments), leading blanks and tabs are ignored. Each line in a fcrontab
       file can be either

       o an environment setting,

       o an option setting,

       o entries based on elapsed system up time,

       o entries based on absolute time (like normal crontab entries), or

       o entries run periodically.

       Any logical line (an entry or an assignment) can be divided into
       several real lines (the lines which end by a newline character) by
       placing a backslash (\) before the newline character (\n).

   THE ENVIRONMENT SETTINGS
       The environment settings are of the form


              name = value

       where the blanks around equal-sign (=) are ignored and optional.
       Trailing blanks are also ignored, but you can place the value in quotes
       (simple or double, but matching) to preserve any blanks in the value.

       When fcron executes a command, it always sets USER, and HOME as defined
       in /etc/passwd for the owner of the fcrontab from which the command is
       extracted. TZ is also defined to the value of the option timezone when
       this option is used. It also defines SHELL to the value of the SHELL
       used to run the command. Fcron uses the value of SHELL from the
       fcrontab if any, otherwise it uses the value from fcron.conf if any, or
       in last resort the value from /etc/passwd. HOME and SHELL may be
       overridden by settings in the fcrontab, but USER may not.  Every other
       environment assignments defined in the user fcrontab are then made, and
       the command is executed.

       By default, fcron will send emails using the email "Content-Type:"
       header of "text/plain" with the "charset=" parameter set to the charmap
       / codeset of the locale in which fcron(8) is started up - i.e. either
       the default system locale, if no LC_* environment variables are set, or
       the locale specified by the LC_* environment variables (see locale(7)).
       You can use different character encodings for emailed fcron job output
       by setting the CONTENT_TYPE and CONTENT_TRANSFER_ENCODING variables in
       fcrontabs, to the correct values of the mail headers of those names.

       Additionally, the special variables MAILFROM and MAILTO allow you to
       tell fcron from/to whom it should email the command's output. Note that
       these are in fact equivalent to global declarations of the options
       mailfrom and mailto (see below). They are used for backward
       compatibility, and it is recommended that you use the options mailfrom
       and mailto directly instead.

   ENTRIES BASED ON ELAPSED SYSTEM UP TIME
       Jobs are scheduled to run once every m minutes of fcron's execution
       (which is normally the same as m minutes of system's execution). The
       time a system is suspended (to memory or disk) is considered as down
       time. To configure such a job, use configuration lines of the form:

       @options frequency command

       where frequency is a time value of the form
       value*multiplier+value*multiplier+...+value-in-minutes as "12h02" or
       "3w2d5h1".  The first means "12 hours and 2 minutes of fcron execution"
       while the second means "3 weeks, 2 days, 5 hours and 1 minute of fcron
       execution". The only valid multipliers are: "VALID TIME MULTIPLIERS"
       meaning: multipliers:      months (4 weeks): m      weeks (7 days): w
       days (24 hours): d      hours (60 minutes): h  seconds: s

       In place of options, user can put a time value: it will be interpreted
       as @first(<time>). If first option is not set, the value of "frequency"
       is used.

       This kind of entry does not guarantee a time and date of execution (as
       the job is delayed at each startup by the time elapsed since the
       shutdown), but should be useful for jobs depending on the number of
       things done by the users (for instance, the filesystem should better be
       checked after a certain amount of use by the users rather than every x
       days, as the system may run from 1 day to x days during that x days
       interval).

       The time remaining before next execution is saved every 1800 seconds
       (to limit damages caused by a crash) and when fcron exits after having
       received a SIGTERM signal, i.e. when systems go down. Thus, this kind
       of entries is particularly useful for systems that don't run regularly.
       The syntax being very simple, it may also useful for tasks which don't
       need to be run at a specific time and date.

       See also: options first, mail, nolog, serial, lavg, nice, runas (see
       below).

   SOME EXAMPLES OF LINES BASED ON ELAPSED SYSTEM UP TIME
       # Get our mails every 30 minutes
       @ 30 getmails -all

       # make some security tests every 48 hours of system up time,
       # force a mail to be sent to root even if there is no output
       @mailto(root),forcemail 2d /etc/security/msec/cron-sh/security.sh

   ENTRIES BASED ON TIME AND DATE
       The second type of fcrontab's entries begins by an optional "&", which
       can be immediately followed by an optional number defining the
       frequency of execution (this is equivalent to option runfreq) or a
       declaration of options; it has five time and date fields, and a shell
       command :

       &options min hrs day-of-month month day-of-week command

       Note that the shell command may be preceded by a user name, which is
       equivalent to runas(<user>): as it is only here for backward
       compatibility you should use option runas (see below) instead. The
       frequency is interpreted as: "run this command after x matches of time
       and date fields". The time and date fields are: "TIME AND DATE FIELDS"
       field: allowed values:      minute: 0-59      hour: 0-23      day of
       month: 1-31      month: 1-12 (or names, see below)      day of week:
       0-7 (0 and 7 are both Sunday, or names)

       A field is always filled by either an asterisk (*), which acts as
       "first-last" range, a single number or a list.

       List are numbers or range separated with commas (,). For instance:
       "2,5,15,23".

       Ranges of number are of the form "<begin>-<end>", where "begin" and
       "end" are included. For example, "3-5" specifies the values 3, 4 and 5.
       You can also add an optional "/number" to a range, where the number
       specifies skips of the number's value through the range. For example,
       "0-23/2" can be used in the hours field to specify command execution
       every other hour. Finally, one or several "~number" can be added to
       turn off some specific values in a range. For example, "5-8~6~7" is
       equivalent to "5,8". The final form of a field is:


              a[-b[/c][~d][~e][...]][,f[-g[/h][~i][~j][...]]][,...]

       where the letters are integers.

       You can also use an asterisk (*) in a field. It acts for "first-last".
       For example, a "*" in the field minute means all minutes from minute 0
       down to minute 59.

       Ranges can be included in a list as a single number. For instance:
       "2,5-10/2~6,15,20-25,30".

       Names can also be used for the "month" and "day of week" fields. To do
       so, use the first three letters of the particular day or month (case
       doesn't matter). Please note that names are used exactly as numbers:
       you can use them in a list or a range.

       If a day of month and a day of week are given, the command will execute
       only when both match with the current time and date unless option dayor
       is set. For example, with the line

       5 10 31 * 7 echo ''
       echo will only be executed days which are a Sunday AND a 31th, at
       10:05.

       See also: options dayor, bootrun, runfreq, mail, nolog, serial, lavg,
       nice, runas (see below).

   SOME EXAMPLES OF ENTRIES BASED ON TIME AND DATE
       # run mycommand at 12:05, 12:35, 13:05, 13:35,
       # 14:05 *and* 14:35 everyday
       & 05,35 12-14 * * * mycommand -u me -o file

       # get mails every hour past 20, 21, 22, and 24 minutes.
       20-24~23 * * * * getmail

       # save our work of the day every night at 03:45 with a low priority
       # unless we are sunday, mail the output to jim and run that job
       # at startup if computer was down at 03:45
       &nice(10),mailto(jim),bootrun 45 03 * * *~0 "save --our work"

   ENTRIES RUN PERIODICALLY
       The third type of fcrontab's entries begin by a "%", followed by a
       keyword from one of 3 different lists, and optional options.

   *LY KEYWORDS
       Those keywords are:

       hourly , daily , monthly , weekly

       Those keywords tell fcron to run the command once from the beginning of
       the corresponding time interval to the end of that time interval. A
       time interval is, for example, the time from Monday 16:20 to Wednesday
       01h43.  For instance, the keyword weekly tells fcron to run a command
       once between Monday and Sunday each week.

       With this two kind of keywords, user must give the needed time fields
       (as defined in "Entries based on time and date" (see above)) to specify
       when the command should be run during each time interval:

       "NEEDED TIME FIELDS FOR EACH KEYWORD" Keywords: must be followed by the
       fields:  hourly, midhourly:  minutes. daily, middaily, nightly, weekly,
       midweekly:  minutes and hours. monthly, midmonthly:  minutes, hours and
       days.

   MID*LY KEYWORDS
       They are similar to the "*ly" ones:

       midhourly , middaily , nightly , midmonthly , midweekly

       They work exactly has the "*ly" keywords, except that the time
       intervals are defined from middle to middle of the corresponding "*ly"
       intervals: midweekly will run a command once from Thursday to
       Wednesday. Note that nightly is equivalent to middaily.

       For example:

       %nightly,mail(no) * 21-23,3-5 echo "a nigthly entry"

       will run the command once each night either between 21:00 and 23:59, or
       between 3:00 and 5:59 (it will run as soon as possible. To change that,
       use option random) and won't send mail (because option mail is set to
       "no").

       See also: options lavg, noticenotrun, strict, mail, nolog, serial,
       nice, runas, random (see below).

   *S KEYWORDS
       They are:

       mins , hours , days , mons , dow

       Those keywords act differently, as follows:

       run this command once during EACH time interval specified, ignoring the
       fields below the keyword in the time interval definition (a hours
       prevents the mins field to be considered as a time interval, but it
       will be used to determine when the line should be run during an
       interval: see the note below) (dow means "day of week").

       Such a keyword is followed by 5 time and date fields (the same fields
       used for a line based on absolute time (see above)). Furthermore, there
       must be some non-matching time and dates in the lines with that kind of
       keyword (i.e. the following is not allowed :

       %hours * 0-23 * * * echo "INCORRECT line!"
       but

       %hours * 0-22 * * * echo "Ok."
       is allowed).

              Note:

              a single number in a field is considered as a time interval:

              %mins 15 2-4 * * * echo
              will run at 2:15, 3:15 AND 4:15 every day.

              But all fields below the keywords are ignored in time interval
              definition:

              %hours 15 2-4 * * * echo
              will run only ONCE either at 2:15, 3:15 OR 4:15.

       See also: option random (see below).

   VIXIE CRON SHORTCUTS
       To ensure a good compatibility with Vixie cron, Vixie cron shortcuts
       are supported. Generally speaking their usage is not recommended as
       they lack some of the flexibility brought by fcron. Also where the
       precise time of execution is not critical, the use lines based on
       elapsed system up time is recommended instead.

       A task using a Vixie cron shortcut is of the form:

       shortcut command

       Below is a list of available shortcuts, plus some fcron-specific
       additions, with their fcron equivalent: "VIXIE CRON SHORTCUTS"
       shortcut: meaning: fcron equivalent: suggested alternative: @reboot Run
       once, at startup @runatreboot,runonce(true)   @resume Run once, at
       resume from suspend/hibernate @runatresume,runonce(true)   @yearly Run
       once a year 0 0 1 1 * @ 12m @annually (same as @yearly) 0 0 1 1 * @ 12m
       @monthly Run once a month 0 0 1 * * @ 1m @weekly Run once a week 0 0 *
       * 0 @ 1w @daily Run once a day 0 0 * * * @ 1d @midnight (same as
       @daily) 0 0 * * *  @hourly Run once an hour 0 * * * * @ 1h

       A few examples:

       # run check_laptop_logs.sh at the first minute of every hour:
       @hourly check_laptop_logs.sh
       # run check_web_server.sh and check_file_server.sh every day at exactly
       # midnight, both at the same time:
       @daily check_web_server.sh
       @daily check_file_server.sh
       # run compress_home_made_app_log_files.sh at exactly midnight
       # on the first day of every month:
       @monthly compress_home_made_app_log_files.sh

       However you might want to replace those task definitions by something
       as:

       # run check_laptop_logs.sh after every hour of system up time:
       @ 60 check_laptop_logs.sh
       # run check_web_server.sh and check_file_server.sh every night between midnight
       # and 3am, one at a time:
       %nightly,serial * 0-3 check_web_server.sh
       %nightly,serial * 0-3 check_file_server.sh
       # Run compress_home_made_app_log_files.sh once a month, only at night
       # when the load is low:
       @monthly,lavg(0.5) * 21-23,0-5 * compress_home_made_app_log_files.sh

       Last, but not least, it should be noted that tasks defined using a
       Vixie cron shortcut will only have the same behaviour as in Vixie cron
       if they are not modified by some earlier option definition. That will
       be the case if you import a Vixie cron crontab into fcron without
       modification, or if you precede the task definition by a reset, e.g.:

       !serial
       @ 10 fcron_task_1
       @ 25 fcron_task_2
       !reset
       @reboot start_unprivileged_user_program
       @daily cleanup_tmp.sh

       In the example above, serial would apply to the last two tasks if we
       hadn't used reset.

   OPTIONS
       The options can be set either for every line below the declaration or
       for an individual line. In the first case, the setting is done on a
       whole line immediately after an exclamation mark (!), while it is done
       after a "&", a "%" or a "@" depending on the type of scheduling in the
       second case. Note that an option declaration in a schedule overrides
       the global declaration of that same option.

       Options are separated by commas (,) and their arguments, if any, are
       placed in parentheses ("(" and ")") and separated by commas. No space
       or surrounding (double-)quote is allowed. A declaration of options is
       of the form


              option[(arg1[,arg2][...])][,option[(arg1[...])]][...]

       where option is either the name of an option or its abbreviation. The
       options are (default value in parentheses): "VALID OPTIONS IN A
       FCRONTAB"

       bootrun

       b      boolean(false)

              Run an &-line at fcron's startup (or system's resume after
              suspend/hibernation) if it should have run during system down
              time.

       dayand boolean(true)

              Perform a logic AND between week and month day.

              See also: options dayor.

       dayor  boolean(false)

              Perform a logic OR between week and month day.

              See also: options dayand.

       erroronlymail
              boolean(false)

              Mail output only if job exited with a non-zero status.

              See also: options mail, mailto, forcemail, nolog.

       exesev boolean(false)

              Can a job be executed several times simultaneously ?

              See also: options serialonce, lavgonce.

       first

       f      time-value

              Delay before first execution of a job based on system up time
              ("@"-lines). Useful in the following case: you have several jobs
              running, say, every hour. By setting different first value for
              each job, you can avoid them to run simultaneously everytime.
              You can also set it to 0, which is useful when used in
              conjunction with option volatile.

       forcemail
              boolean(false)

              Mail output even if zero-length.

              Setting this option to true will also set mail to true.

              See also: options mail, mailto, erroronlymail, nolog.

       jitter integer(0)

              Run the task between 0 and jitter seconds later than it should
              have been run. This options only applies to &-lines and is
              intended for systems where many jobs are supposed to be started
              at the same minute: the jitter option will randomly spread the
              start of all those jobs across the first jitter seconds of the
              minute instead of starting all of them at the first second of
              the minute. The argument must be between 0 and 255 (inclusive).

              See also: option random.

       lavg   real(0) real(0) real(0)

              Set the values of the 1, 5 and 15-minute (in this order) system
              load average values below which the job should run. The values
              have a maximum of 1 decimal (i.e. "2.3"): if there are more than
              1 decimal, the value will be rounded off. Set a value to 0 to
              ignore the corresponding load average (or all of the values to
              run the job regardless of the load average).

              See also: options lavg1, lavg5, lavg15, until, lavgonce, lavgor,
              lavgand, strict, noticenotrun.

       lavg1

       lavg5

       lavg15 real(0)

              Set the threshold of, respectively, the 1, 5 or 15 minutes
              system load average value. Set one of them to 0 to ignore the
              corresponding load average.

              See also: options lavg.

       lavgand
              boolean(true)

              Perform a logic AND between the 1, 5 and 15 minutes system load
              average values.

              See also: options lavg, lavgor.

       lavgonce
              boolean(1)

              Can a job be queued several times in lavg queue simultaneously?

              See also: options lavg.

       lavgor boolean(false)

              Perform a logic OR between the 1, 5 and 15 minutes system load
              average values.

              See also: options lavg, lavgand.

       mail

       m      boolean(true)

              Mail output (if any) or not.

              Setting this option to false will also set forcemail to false.

              See also: options mailto, forcemail, erroronlymail, nolog.

       mailfrom
              email-address(user job is run as)

              Use this as the 'From:' address when mailing job outputs.  It
              can be either a single user-name or a fully qualified email
              address.  In the former case, fcron will add the hostname
              automatically.  Setting mailfrom to an empty value is equivalent
              to resetting it to the default value of the name of the user the
              job is run as.

              See also: options mail, forcemail, erroronlymail, nolog, mailto.

       mailto email-address(name of file's owner)

              Mail output (if needed) to "email-address". It can be either a
              single user-name or a fully qualified email address. In the
              former case, fcron will add the hostname automatically.  A
              mailto declared and empty (string "") is equivalent to
              "mail(false)".

              See also: options mail, forcemail, erroronlymail, nolog,
              mailfrom.

       nice

       n      nice-value

              Change job priority. A nice-value is an integer from -20
              (highest priority) to 19 (lowest) (only root is allowed to use a
              negative value with this option).

       nolog  boolean(false)

              If set to true, log only errors for the corresponding job(s).
              May be useful for jobs running very often, and/or to reduce disk
              access on a laptop.

              See also: options mail, mailto, erroronlymail, forcemail.

       noticenotrun
              boolean(false)

              Should fcron mail user to report the non-execution of a %-job or
              an &-job? (because of system down state (including
              suspend/hibernation) for both or a too high system load average
              for the latter)

              See also: options lavg, strict.

       random boolean(false)

              In a line run periodically, this option answers the question:
              should this job be run as soon as possible in its time interval
              of execution (safer), or should fcron set a random time of
              execution in that time interval? Note that if this option is
              set, the job may not run if fcron is not running during the
              whole execution interval. Besides, you must know that the random
              scheme may be quite easy to guess for skilled people: thus, you
              shouldn't rely on this option to make important things secure.
              However, it shouldn't be a problem for most uses.

              See also: option jitter.

       rebootreset
              boolean(false)

              When set to true, fcron will act as if the task was a new one
              every time the OS reboots. This is very similar to the option
              volatile but based on the OS reboots instead of fcron restarts.
              You may also want to use option first if you use fcron that way.

              See also: options first, volatile, runonce, runatreboot.

       reset  boolean

              Reset all the options to default.

       runas  user-name

              Run with "user-name" permissions and environment (only root is
              allowed to use this option).

       runatreboot
              boolean(false)

              If set to true, the task will be run at system startup (i.e.
              immediately after the --sleeptime delay -- by default, 20
              seconds -- when the fcron daemon starts the first time after the
              OS has booted). This is in addition to the regular schedule
              which won't be modified by this option.

              For instance, if a program should be started automatically and
              run from 7am to 6pm, you could use the following dfcrontab
              definitions:

              &runatreboot 0 6 * * 1-5 start_my_program.sh
              & 0 7 * * 1-5 stop_my_program.sh

              See also: options volatile, runonce, rebootreset.

       runfreq

       r      integer

              Run every "runfreq" matches of time and date. (this option is
              ignored for lines based on elapsed system up time).

       runonce
              boolean(false)

              Do not re-schedule the task after it has run once, until the
              next OS reboot (if volatile is not set) or until the next fcron
              daemon restart (if volatile is set).

              See also: options volatile, rebootreset, runatreboot.

       serial

       s      boolean(false)

              Fcron runs at most 1 serial jobs (ie. for which the option
              serial is set to true), and the same number of lavg serial jobs
              (ie. for which both option serial and lavg (or lavg1 or lavg5 or
              lavg15) are set to true) simultaneously. This value may be
              modified by fcron's option -m. This option is especially useful
              when used with big jobs in order to limit the system overload.

              See also: options serialonce, lavg.

       serialonce
              boolean(0)

              Can a job be queued several times in serial queue
              simultaneously?

              See also: options exesev, lavgonce.

       stdout boolean(false)

              If fcron is running in the foreground, then also let jobs print
              to stderr/stdout instead of mailing or discarding it.

              See also: fcron's option --once in fcron(8).

       strict boolean(true)

              When a lavg %-job is at the end of a time interval of execution,
              should it be removed from the lavg queue (strict(true), so the
              job is not run) or be let there until the system load average
              allows its execution (strict(false))?

              See also: options lavg, noticenotrun.

       timezone
              timezone-name(time zone of the system)

              Run the job in the given time zone. timezone-name is a string
              which is valid for the environment variable TZ: see the
              documentation of your system for more details. For instance,
              "Europe/Paris" is valid on a Linux system. This option handles
              daylight saving time changes correctly. The TZ environment
              variable is set to the value of timezone when a job defining
              this option is run.

              Please note that if you give an erroneous timezone-name
              argument, it will be SILENTLY ignored, and the job will run in
              the time zone of the system.

              WARNING: do *not* use option timezone and option tzdiff
              simultaneously! There is no need to do so, and timezone is
              cleverer than tzdiff.

              See also: options tzdiff.

       tzdiff integer(0)

              WARNING: this option is deprecated: use option timezone instead!

              Time zone difference (in hours, between -24 and 24) between the
              system time, and the local real time. This option allows a user
              to define its & and %-lines in the local time. Note that this
              value is set for a whole fcrontab file, and only the last
              definition is taken into account. tzdiff is quite stupid: it
              doesn't handle daylight saving changes, while option timezone
              does, so you should use the latter.

              See also: options timezone.

       until  time-value(0)

              Set the timeout of the waiting of the wanted system load average
              values. If the timeout is exceeded, the job runs no matter the
              load average. Set until to 0 to remove the timeout.

              See also: options lavg.

       volatile
              boolean(false)

              When set to true, the job is based on a "volatile" system up
              time, i.e. restart counting each time fcron is started, which is
              useful when fcron is started by a script running only, for
              instance, during a dialup connection: the "volatile" system up
              time then refers to the dialup connection time. You may also
              want to use option first if you use fcron that way.

              See also: options first, stdout, rebootreset, lines based on
              elapsed system up time, fcron's command line argument --once in
              fcron(8).

       A boolean argument can be non-existent, in which case parentheses are
       not used and it means true; the string "true", "yes" or 1 to mean true;
       and the string "false", "no" or 0 to mean false. See above for
       explanations about time value (section "entries based on elapsed system
       up time").

       Note that dayand and dayor are in fact the same option: a false value
       to dayand is equivalent to a true to dayor, and reciprocally a false
       value to dayor is equivalent a true value to dayand. It is the same for
       lavgand and lavgor.

       Note a special case to be handled: A job should be entered into the
       serial queue, *but* the previous entry for this job has not been
       completed yet, because of high system load or some external event.
       Option serialonce answers the question: should the new entry of the job
       be ignored? This way one can distinguish between jobs required to run a
       certain number of times, preferably at specified times, and tasks to be
       performed irrespective of their number (-> serialonce(true)), which
       make the system respond faster.

       The same considerations apply for the load average queue, and can be
       expressed with option lavgonce.

       Moreover, if the serial or the lavg queue contains respectively more
       than 30 and 30 jobs, any new job is refused and not run to avoid an
       overwhelming of system resources. In this case, an error message is
       logged through syslog.

       Finally, if jobs remain in the lavg or serial queues when fcron stops,
       they will be put once in the corresponding queue on startup (their
       order may not be conserved).

   AN EXAMPLE OF AN OPTION DECLARATION:
       !reset,serial(true),dayor,bootrun(0),mailto(root),lavg(.5,2,1.5)

EXAMPLES
   AN EXAMPLE OF A USER FCRONTAB
       # use /bin/bash to run commands, ignoring what /etc/passwd says
       SHELL=/bin/bash

       # mail output to thib, no matter whose fcrontab this is
       !mailto(thib)

       # define a variable which is equivalent to " Hello thib and paul! "
       # here the newline characters are escaped by a backslash (\)
       # and quotes are used to force to keep leading and trailing blanks
       TEXT= " Hello\
        thib and\
        paul! "

       # we want to use serial but not bootrun:
       !serial(true),b(0)

       # run after five minutes of execution the first time,
       # then run every hour
       @first(5) 1h   echo "Run every hour"

       # run every day
       @ 1d echo "fcron daily"

       # run once between in the morning and once in the afternoon
       #  if systems is running at any moment of these time intervals
       %hours * 8-12,14-18 * * * echo "Hey boss, I'm working today!"

       # run once a week during our lunch
       %weekly * 12-13 echo "I left my system on at least once \
        at lunch time this week."

       # run every Sunday and Saturday at 9:05
       5 9 * * sat,sun echo "Good morning Thibault!"

       # run every even days of march at 18:00, except on 16th
       0 18 2-30/2~16 Mar * echo "It's time to go back home!"

       # the line above is equivalent to
       & 0 18 2-30/2~16 Mar * echo "It's time to go back home!"

       # reset options to default and set runfreq for lines below
       !reset,runfreq(7)

       # run once every 7 matches (thanks to the declaration above),
       # so if system is running every day at 10:00, this will be
       # run once a week
       & 0 10 * * * echo "if you got this message last time 7 days ago,\
        this computer has been running every day at 10:00 last week.\
        If you got the message 8 days ago, then the system has been down \
        one day at 10:00 since you got it, etc"

       # wait every hour for a 5 minutes load average under 0.9
       @lavg5(0.9) 1h echo "The system load average is low"

       # wait a maximum of 5 hours every day for a fall of the load average
       @lavgand,lavg(1,2.0,3.0),until(5h) 1d echo "Load average is going down"

       # wait for the best moment to run a heavy job
       @lavgor,lavg(0.8,1.2,1.5),nice(10) 1w echo "This is a heavy job"

       # run once every night between either 21:00 and 23:00 or
       #   between 3:00 and 6:00
       %nightly,lavg(1.5,2,2) * 21-23,3-6 echo "It's time to retrieve \
        the latest release of Mozilla!"

FILES
       /usr/local/etc/fcron.conf
              Configuration file for fcron, fcrontab and fcrondyn: contains
              paths (spool dir, pid file) and default programs to use (editor,
              shell, etc). See fcron.conf(5) for more details.

       /usr/local/etc/fcron.allow
              Users allowed to use fcrontab and fcrondyn (one name per line,
              special name "all" acts for everyone)

       /usr/local/etc/fcron.deny
              Users who are not allowed to use fcrontab and fcrondyn (same
              format as allow file)

       /usr/local/etc/pam.d/fcron (or /usr/local/etc/pam.conf)
              PAM configuration file for fcron. Take a look at pam(8) for more
              details.

SEE ALSO
       fcrontab(1),

       fcrondyn(1),

       fcrontab(5),

       fcron.conf(5),

       fcron(8).

       If you're learning how to use fcron from scratch, I suggest that you
       read the HTML version of the documentation (if your are not reading it
       right now! :) ): the content is the same, but it is easier to navigate
       thanks to the hyperlinks.

AUTHOR
       Thibault Godouet <fcron@free.fr>

12/05/2021                     05 December 2021                    FCRONTAB(5)